The present invention relates generally to electric motors, and particularly to a modular motor that facilitates motor construction.
Submersible electric motors are used in submersible pumping systems to lift wellbore fluids from depths of up to several thousand feet. A conventional motor used to provide the equivalent pumping power on the surface cannot be used in a wellbore because the diameter of such a motor would be too wide to fit into the wellbore. Therefore, as compared to short, thick surface motors, the stators of submersible electric motors are relatively thin and extremely elongated.
Elongating the stator allows the motor to produce the required torque to drive a pump by developing magnetic force over a stator of a much larger length. Thus, if long enough, a motor that produces a relatively smaller torque per foot can produce a sufficient total torque. Depending on the horsepower required of the motor, electric submersible pumping system motors can utilize stator assemblies thirty feet long or more. Preparation of the stator windings requires long, thin polished rods that serve as needles for pulling the insulated, conductor wires through a lengthy assembly of stator laminations. This conventional process is a comparatively slow and expensive process for manufacturing such motors. Additionally, repair or rebuilding of such motors often requires complete destruction or tear down of the motor with little component repair value due to the unitary stator assembly.
It would be advantageous to have a modular motor that could be used to construct motors in the field, such as motors utilized in electric submersible pumping systems. Benefits of such a modular construction would include reduced cost and assembly time, reduced repair time and reduced motor component inventory.
The present invention features a modular electric motor. The modular electric motor comprises a plurality of motor sections selectively coupleable, mechanically and electrically, to form electric motors in a variety of desired lengths. The modular electric motor features a rotor in each motor section that is drivingly coupleable to at least one other motor section.
According to another aspect of the invention, a submersible pumping system is featured. The submersible pumping system includes a submersible electric motor and a submersible pump. The submersible electric motor has a plurality of motor sections which are mechanically and electrically coupleable to form a motor of a desired length. Each motor section has a modular stator section and a modular rotor section.
According to another aspect of the invention, a method is provided for facilitating the assembly of an electric motor. The method features the act of manufacturing a plurality of motor sections having modular stator and rotor components. The method further includes determining a desired motor horsepower for a given application, and connecting the modular components to assemble a motor of the required length and horsepower.